1. Field of the Invention
The present invention relates to fixtures and a fitting structure for an eyeglass lens, and in particular relates to fixtures and a fitting structure for an eyeglass lens suitable for fitting the eyeglass lens between a bridge and an end piece of a two-point type eyeglass frame.
2. Description of the Related Art
There are various kinds of the two-point type eyeglass frames; for example, the generally known is that comprises an I-shaped bridge, a nose pad to be attached to the bridge, an L-shaped end piece, and a temple swingablly attached to the end piece via a hinge, etc.
In order to attach an eyeglass lens between the bridge and the end piece of an eyeglass frame of such a structure: first, through-holes are formed at the inside and outside rims of the eyeglass lens by using a tool such as a drill; two of the eyeglass lenses are prepared and arranged to have a predetermined spacing therebetween; the bridge is arranged between the both eyeglass lenses; fitting portions at both ends of the bridge are located over top faces of the eyeglass lenses; a hole in each of the fitting portions is aligned with the through-hole of the inside rim of the eyeglass lens; a setscrew is inserted through both the holes via a washer from the top side of the eyeglass lens; a nut is screwed to a portion of the setscrew protruded from the back side of the eyeglass lens via a washer so as to be tightened at a predetermined torque; a locking cap nut is screwed to the end portion of the setscrew so as to be tightened at a predetermined torque.
Then, the end piece is located at the outside rim of each eyeglass lens; a fitting portion at one end of the end piece is located over the top face of the eyeglass lens; a hole in the fitting portion is aligned with the through-hole in the outside rim of the eyeglass lens; a setscrew is inserted through both the holes via a washer from the top side of the eyeglass lens; a nut is screwed to a portion of the setscrew protruded from the backside of the eyeglass lens via a washer so as to be tightened at a predetermined torque; a locking cap nut is screwed to the end portion of the setscrew so as to be tightened at a predetermined torque.
In such a manner, the two eyeglass lenses are respectively attached between the bridge and the end piece of the two-point type eyeglass frame.
However, when the nut is screwed and tightened to the setscrew, the eyeglass lens may be occasionally cracked from the hole portion due to an excessive stress in the thickness direction of the eyeglass lens, so that special attention is required for the assembling and a skilled technique is also demanded in the assembling.
Moreover, since th e setscrews, the washers, the nuts, and the cap screws are used, the costs of parts and assembling rise due to a large number of parts.
Further, when the nut is screwed and tightened to the setscrew, since a special tool is required, inexperienced workers may occasionally damage the eyeglass lens.
Also, on the backside of the eyeglass lens located are the nut and the cap screw, which obstruct the visibility and wiping of the eyeglass lens.